BALTIMORE — Mayor Stephanie Rawlings-Blake called on Wednesday for the Justice Department to conduct a civil rights investigation of the city’s Police Department to determine whether officers have engaged in unconstitutional patterns of abuse or discrimination.

Her request came days after the state’s attorney for Baltimore filed criminal charges against six officers involved in the arrest of Freddie Gray, who died April 19 after being injured while in police custody, sparking large demonstrations, arson and looting.

“We all know that Baltimore continues to have a fractured relationship between the police and the community,” Ms. Rawlings-Blake said at a news conference. “We have to have a foundation of trust, and I believe that we need the assistance of the Department of Justice and the civil rights investigation to shore up that foundation, which is weak right now in this city.”

She added, “I’m willing to do what it takes to reform my department.”

Her call puts significant pressure on the Justice Department to begin a “pattern-or-practice” investigation of the Baltimore police, which would look into whether officers used excessive force, carried out street stops based on the race of individuals or arrested people without probable cause. Separately, the Justice Department is also investigating whether the police violated Mr. Gray’s civil rights.

This inquiry would be similar to reviews the department has conducted in about 20 cities around the country during the past six years, including in Ferguson, Mo., after the fatal police shooting last year of Michael Brown.

Dena Iverson, a Justice Department spokeswoman, said that the agency had received the mayor’s request, and that Attorney General Loretta E. Lynch “is actively considering that option in light of what she heard from law enforcement, city officials, and community, faith and youth leaders in Baltimore.”

Two United States officials, who declined to be named because they were not authorized to speak publicly, said that the Justice Department was likely to open a civil rights investigation but that no decision had been made.

Ms. Rawlings-Blake’s call came after two weeks of turmoil in which her leadership was questioned amid widespread demonstrations against the police. The Justice Department has been considering a civil rights investigation of Baltimore for years, current and former officials said, but held off because the city appeared willing to make changes. In the fall, Ms. Rawlings-Blake asked for the Justice Department’s help in examining the practices and procedures of the force. Those visits are likely to result in nonbinding recommendations in the next few weeks.

On Tuesday, Bernard C. Young, the president of the City Council, and 10 other members sent a letter to Ms. Lynch asking for “a full-scale civil rights investigation” of the Baltimore police, which the group said it had also asked Eric H. Holder Jr. to open in October 2014 when he was the attorney general.

“The systemic mistreatment of members of the African-American community by some officers within the Baltimore Police Department helped contribute to a strained relationship between police and the citizens who depend on them for protection and service,” the letter read in part. “The city of Baltimore is in desperate need of a binding federal review of the police department in order to repair this fractured relationship.”

During an interview Wednesday, Mr. Young said the city needed more than the earlier review. “It’s not binding," he said. "The commissioner could say, ’Thank you, but no thanks.’ ”

He also said the majority of Baltimore’s police officers did good work. “The citizens of Baltimore have been crying out for years because of the mistreatment and mistrust of the Police Department — and it’s not the entire Police Department,” he said.

Jill P. Carter, a member of the Maryland House of Delegates who represents Baltimore, said that she feared that policing practices would not change once all the attention moved on from Mr. Gray’s death.

“I’m skeptical,” she said. “There’s already been lawsuits where there have been consent decrees and orders to be followed where there’s very little evidence that they’ve been followed.”

Just last week, the mayor said at a televised community meeting that “nobody wants the Department of Justice to come and take over our city.” The Justice Department does not take over cities and, even in civil rights investigation, does not take over the management of police departments.

The mayor was under tremendous political pressure, Ms. Carter said.

“The attention that’s been focused on our city is now requiring the political leadership of the city to do something,” she said. Regarding the mayor’s call for a Justice Department investigation, Ms. Carter added, “This is one tool in the toolbox the mayor can use to try to fix what’s wrong.”

The Baltimore police union said it welcomed a federal inquiry. “We, too, have many issues with current policies and procedures of the department,” Gene Ryan, the president of the Fraternal Order of Police Lodge 3, said in a statement.

Although it is uncommon for a mayor to seek a Justice Department civil rights inquiry of its police department, it is not unprecedented. Recent investigations of the police in Cleveland and in Washington, for example, were opened after the federal authorities received requests by the mayors and police chiefs of those cities.

“Asking for a pattern-or-practice investigation is politically very smart and gives enormous cover to a political leader because they are calling for a thorough investigation,” said William Yeomans, a law professor at American University, who is a former Justice Department official. “The burden then shifts to the federal government to actually get the work done and do the investigation.”

The inquiries as a rule take several months to more than one year and examine things like hiring practices, arrests, training procedures, and incidents of force and possible racial profiling. Ms. Rawlings-Blake said Wednesday that she had asked the Justice Department to investigate “if our police department has engaged in a pattern of stops, searches or arrests that violate the Fourth Amendment,” and further, what factors “contribute to excessive force or discriminatory policing.”

The Fourth Amendment prohibits unreasonable searches and seizures, and a federal investigation into whether Baltimore’s officers had violated that constitutional protection would probably cover a wide array of the everyday work police officers perform, including making arrests, carrying out stop-and-frisks and obtaining search warrants.

Once the federal investigation is complete, the Justice Department and city officials typically conduct negotiations about the specific reforms in policing that federal officials have sought and the speed at which the new policies are to be put in place.

If an agreement is not reached, the Justice Department can move to sue the department, which usually results in a consent decree in which a federal court monitors the pace of reforms.

Elijah E. Cummings, a member of the House of Representatives, said Wednesday that he supported a civil rights inquiry, adding, “Mr. Gray’s death is only the most recent case underscoring the need to examine our police department from top to bottom.”

Also Wednesday, Gov. Larry Hogan announced an end to the state of emergency that was put in place April 27 during rioting in the city. He said the last of the National Guard troops and other police called up to assist had left.

In total, 3,000 National Guard troops and 1,000 additional police officers had been called in to assist, he said.

Mr. Hogan said 250 businesses had been burned, looted or vandalized, and more than 170 cars were damaged. He added that he supported the mayor’s call for a civil rights inquiry of the police.

“I think that’s probably a step in the right direction,” Mr. Hogan said.

Stephen Babcock contributed reporting from Baltimore, and Richard Pérez Peña and Matt Apuzzo from New York.

A version of this article appears in print on , Section A, Page 15 of the New York edition with the headline: Mayor Wants Justice Dept. to Investigate in Baltimore. Order Reprints | Today’s Paper | Subscribe